JPS5835910A - Ignition coil-built-in with high voltage diode - Google Patents

Abstract

PURPOSE:To blunt the rising wave form of a high-frequency voltage to be generated by spark discharge, and to mitigate concentration of voltage in a diode built in an ignition coil when ignition energy generated from the ignition coil is to be divided and to be distributed to ignition plugs of the plural number by a method wherein a ferrite core is provided at the edge part of a lead wire on the anode side of the diode. CONSTITUTION:The high-tension diode D1 is accommodated in a plastic case 18 positioning between the ignition coil and the ignition plugs, an epoxy resin composite 30 is poured in, and is made to be hardened to constitute the high-tension diode part. Moreover the lead wire 103 on the anode side to be protruded from the upper edge of the diode D1 is led out outside penetrating the inside of a high-tension terminal 19 inserted in the upper edge of the case 18, while at this time, the ferrite core 17 to surround the lead wire thereof is provided at the edge part of the lead wire 103 positioning in the case 18. Accordingly the rising wave form of high-frequency voltage generated by spark discharge of the spark plugs is smoothed, and voltage withstand performance of the diode is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition device for an internal combustion engine, and more particularly to an ignition coil with a built-in high-voltage diode that distributes ignition energy supplied from an ignition coil using a high-voltage diode and distributes the power to a plurality of spark plugs.

The operation of the ignition system for an internal combustion engine to which the present invention is applied will be explained.

FIG. 1 is an ignition system circuit diagram of a four-cylinder automobile engine to which the present invention is applied. Primary coil 2.3 of ignition coil 1
A common end of each is connected to the positive terminal of the battery 4, and the other end is connected to the respective power transistor Ql through the diodes D5 and D6 of the amplifier 5.

Connected to Q2. On the other hand, the output terminal 61 of the secondary coil 6 is connected to the cathode of the high voltage diode DI and the anode of the high voltage diode D2.

Further, the other output terminal 62 is connected to the cathode of the high voltage diode D3 and the anode of the high voltage diode D4. These high pressure diodes D1 to D4 are connected to a spark plug P1 installed in the first cylinder of the engine, a spark plug P2 installed in the second cylinder, a spark plug P3 installed in the third cylinder, and a spark plug P3 installed in the fourth cylinder. Connected to installed ignition plug 3 lug P4.

FIG. 2 is a diagram illustrating the operation of the ignition system circuit shown in FIG. 1. An electric signal 81.82 synchronized with the rotation of the engine is applied from the input terminal 51.52 of the amplifier 5, and the timing T I -
Between T 2 and 15-16, the value of Sl is 1, and T
The value of S2 is 1 between 3 and T4 and between T7 and T8. In this way, when the value of 81°S2 is alternately set to 1, the power transistors Q1 and Q2 are alternately turned on, and currents II and I2 alternately flow through some of the coils 2 and 3.

In addition, the 'Kanryu 11. The waveform of I2 is a sawtooth wave as shown in the figure.

Immediately as described above, when the current II flowing through the secondary coil 2 is cut off, an inertial high voltage AI shown by the solid line is generated in the secondary coil 6, and the high voltage diode DI is generated.

This high voltage is applied to the spark plugs PI and P4 via D4, causing spark discharges Vl and V4 to be generated in the spark plugs PL and P4. Similarly, when the current flowing through part of the coil 3 is interrupted, the high voltage A2 with the polarity shown by the broken line is applied to the secondary coil 6.
occurs, and the high voltage diode D2. D3 via spark plug P2. A high voltage is applied to spark plug P3, and spark plug P2.
Spark discharge at P3 V2. Generate V3.

The pistons of the 1st and 4th cylinders have a crank angle of 3600
They have different positional relationships, and in the ignition timing of the first cylinder, the fourth
The cylinder has an exhaust stroke. Therefore, as mentioned above, the first
Even if spark discharge occurs simultaneously in the spark plug P1 of the cylinder and the spark plug P4 of the fourth cylinder, the operation of the engine will not be affected. The same can be said for other spark plugs.

The bottom row of the figure shows the relationship between the crank angle and the above-mentioned ignition timing. Spark discharge is generated twice in each spark plug during two revolutions of the crank, and the spark plug returns to its initial state.

Here, a voltage equal to the discharge voltage of the spark plugs P1-P4 is applied in the opposite direction to the high-voltage diodes D1-D4 during operation of the engine. For example, at the ignition timing of the first cylinder, that is, at timing T2, a high voltage equal to the discharge voltage of the spark plug P1 is applied to the high voltage diode D2 in the opposite direction. The discharge voltage of this spark plug varies depending on the operating conditions and engine, but can be up to 30KV4 degrees. Therefore, the reverse withstand voltage of the high voltage diodes D1 to D4 is required to be 3°KV or more. In order to obtain this reverse withstand voltage, the high voltage diodes D1 to D4 have a structure as shown in FIG. Electrodes 102 and lead wires 103 are attached to both ends, and these are integrally molded with glass 104. Next, the reverse voltage applied to the high voltage diodes D1 to D4 is set to E.
. The voltage applied to each silicone pellet 101 when the silicone pellets 101 are closed will be explained.

When the frequency of the applied voltage is low, the voltage is equally distributed to each silicone pellet 101, and if the number of silicone pellets is n, then the voltage E applied to each silicone pellet 101 is n. , is E. , =Eo/n. but,
In the ignition system, when a spark discharge is fully generated in the ignition plug, a high frequency voltage with a rise time of 10 nsW is applied to the high voltage diodes D1 to D4. For this high frequency voltage, the voltage shared by silicone pellets) 101,
It is determined by the capacitance of the silicone pellet 101 and the distributed capacitance between the silicone pellet 101 and the ground, but since both the capacitance and the distributed capacitance of the high voltage diodes D1 to D4 are very small, an equal voltage is not applied, and the high voltage Silicone pellet 1 on the anode side of diodes D1 to D4
01 - Voltage concentration occurs, and the silicone pellet 10
1 includes E mentioned above. The voltage is significantly larger than t = E o /''.

It will be done. As a result, even if the number of laminated silicone pellets 101 is increased, the reverse withstand voltage of the high voltage diode DI-D4 cannot be significantly increased, and the ignition energy is distributed by the high voltage diodes and distributed to multiple spark plugs. In order to put an ignition system for internal combustion engines into practical use, it is necessary to solve this problem and to develop a high-voltage diode that can secure a reverse withstand voltage of 30 KV or more even against the high-frequency voltage when a spark discharge is generated by a spark plug. It was necessary to develop a high-voltage diode arrangement to alleviate voltage concentration.

The present invention has been made in view of the above points, and is generated in a part of the silicone pellet 101 when the high frequency voltage generated when spark discharge occurs in the ignition plugs P1 to P4 is applied to the high voltage diode DI-D4. The purpose of the present invention is to provide an ignition coil with a built-in high-voltage diode that is compact and has excellent withstand voltage performance by providing a structure that alleviates voltage concentration.

The present invention provides lead wires 103 of high voltage diodes D1 to D4.
By attaching a ferrite core to the ignition glove P
This is characterized in that the rise time of the high frequency voltage generated by the spark discharge of I-P4 is smoothed out, and the voltage concentration on the silicone pellet 101 is alleviated.

Hereinafter, a detailed explanation will be given based on the example shown in the figures.

FIG. 4 is a cross-sectional view of an ignition coil with a built-in high-voltage diode to which an embodiment of the present invention is applied, FIG. 5 is a detailed view of the installation of the high-voltage diode p1 in FIG. 4, and FIGS. The same parts are given the same reference numerals.

Part of the coils 2 and 3 are wound around the bobbink.
The beginnings of winding of the secondary coil 3 are connected to the primary terminal 9, and the end of the winding of the secondary coil 3 is connected to the primary terminal 10. On the other hand, the secondary coil 6 is housed in a case 14 made of synthetic resin, and a portion of the secondary coil 6 is
, 3, the secondary coil 6 is wound in layers around two bobbins 11 and then connected in series and housed in the case 14.

End winding ends 61 and 62 of the secondary coil 6 are connected to secondary terminals 12 and 13 attached to the case 4, respectively. After inserting the bobbin 7 wound with the secondary coils 2 and 3 into the center hole of the case 14 housing the secondary coil 6, the epoxy resin composition 30 is impregnated under reduced pressure, and then Transfer to heat and harden. An L-shaped core 15 is inserted into the center hole of the bobbin 7 around which the secondary coils 2 and 3 are wound, and combined with the core 16 surrounding the case 4 to form a set of closed magnetic circuit iron cores.

The high voltage diodes D1 to D4 are shown in FIG. 3, and a ferrite core 17 is attached to a lead wire 103 on the anode side, and is housed in a case 18 made of synthetic resin. One ends of the high-voltage diodes D1 to D4 are connected to high-voltage terminals 19, 20, 21, and 22 integrally formed in the case 18, respectively. Further, the other ends of the high voltage diodes DI, D2 are connected to the diode terminals 23 attached to the case 18, and the high voltage diodes D3. The other end of D4 is similarly connected to the diode terminal 24. After injecting the epoxy resin composition 30 into this case 18, it is heated and cured to form a high voltage diode section. Further, the diode terminals 23, 24 are connected to the secondary terminals 12, 13, and all of the above components are integrally injection molded with synthetic resin 25 to form the ignition coil le.

As explained above, according to the present invention, the rising multi-waveform of high-frequency voltage caused by spark discharge of a spark plug can be smoothed by a simple method of attaching a ferrite core to the lead wire on the anode side of a high-voltage diode. To provide an ignition coil with a built-in high-voltage diode that is small and has excellent withstand voltage performance, since the voltage concentration on the silicone pellet can be alleviated and the withstand voltage performance of the high voltage diode can be greatly improved. Can be done.

In addition, in this embodiment, the lead wire of the high voltage diode D1 is
I explained the case where Elite Core 17 was installed,
As shown in FIG. 6, connect the ferrite core 17 to the lead wire 1.
A high-voltage diode attached to 03 and molded with glass 104 also has the same effect as the present invention.

[Brief explanation of the drawing]

Figure 1 is the ignition system circuit diagram of a four-cylinder automobile engine, Figure 2
The figures are diagrams explaining the operation of the ignition system circuit shown in Fig. 1, Fig. 3 is a sectional view of a high voltage diode, and Fig. 4 shows an embodiment of the present invention. FIG. 5 is a cross-sectional view of the ignition coil with a built-in high-voltage diode, and is a detailed view of the high-voltage diode installation part, which is the main part of the present invention. FIG. 6 is a sectional view of a high voltage diode showing a modification of the present invention. 1...Ignition coil, 2.3...-Next coil, 4...
・Battery, 5... Amplifier, 6... Secondary coil, 7
...Bobbin, 8.9.10...-Next terminal, 11...
・Bobbin, 12° 13...Secondary terminal, 14...Case
=m%15.16...core, 17...ferrite core, 18...case, 19°20.21.22...
High voltage terminal, 23.24...Diode terminal, 25...
- Synthetic resin, 30... Epoxy resin composition, 61.
62... End of winding of secondary coil, 101... Silicone pellet, 102... Electrode, 103... Lead wire, 104... Glass mold. Agent Patent Attorney Aki Takahashi 1 Figure 2 Figure 'f A-1:1 Tea 3 Figure DI, θ2. f)3. θ4 jp'+ hard

Claims (1)

[Claims] 1. In an ignition coil with a built-in high-voltage diode that distributes ignition energy supplied from the ignition coil by a high-voltage diode and distributes power to a plurality of spark plugs, a ferrite core is attached to the lead wire of the high-voltage diode. Ignition coil with built-in high voltage diode. ZIFF The ignition coil with a built-in high-voltage diode according to claim 1, wherein a ferrite core is attached to the lead wire on the anode side of the high-voltage diode.